1 files changed, 388 insertions, 0 deletions
diff --git a/vendor/github.com/bytedance/sonic/internal/resolver/fields.go b/vendor/github.com/bytedance/sonic/internal/resolver/fields.go
new file mode 100644
index 000000000..614bef4e5
--- /dev/null
+++ b/vendor/github.com/bytedance/sonic/internal/resolver/fields.go
@@ -0,0 +1,388 @@
+/**
+ * Copyright 2025 ByteDance Inc.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     https://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package resolver
+
+import (
+	"reflect"
+	"sort"
+	"strings"
+	"unicode"
+	"unicode/utf8"
+
+	"github.com/bytedance/sonic/internal/encoder/alg"
+)
+
+type StdField struct {
+    name        string
+    nameBytes   []byte
+    nameNonEsc  string
+    nameEscHTML string
+    tag         bool
+    index       []int
+    typ         reflect.Type
+    omitEmpty   bool
+    omitZero    bool
+    isZero      func(reflect.Value) bool
+    quoted      bool
+}
+
+type StdStructFields struct {
+    list      []StdField
+    nameIndex map[string]*StdField
+    byFoldedName map[string]*StdField
+}
+
+func typeFields(t reflect.Type) StdStructFields {
+	// Anonymous fields to explore at the current level and the next.
+	current := []StdField{}
+	next := []StdField{{typ: t}}
+
+	// Count of queued names for current level and the next.
+	var count, nextCount map[reflect.Type]int
+
+	// Types already visited at an earlier level.
+	visited := map[reflect.Type]bool{}
+
+	// Fields found.
+	var fields []StdField
+
+	// Buffer to run appendHTMLEscape on field names.
+	var nameEscBuf []byte
+
+	for len(next) > 0 {
+		current, next = next, current[:0]
+		count, nextCount = nextCount, map[reflect.Type]int{}
+
+		for _, f := range current {
+			if visited[f.typ] {
+				continue
+			}
+			visited[f.typ] = true
+
+			// Scan f.typ for fields to include.
+			for i := 0; i < f.typ.NumField(); i++ {
+				sf := f.typ.Field(i)
+				if sf.Anonymous {
+					t := sf.Type
+					if t.Kind() == reflect.Pointer {
+						t = t.Elem()
+					}
+					if !sf.IsExported() && t.Kind() != reflect.Struct {
+						// Ignore embedded fields of unexported non-struct types.
+						continue
+					}
+					// Do not ignore embedded fields of unexported struct types
+					// since they may have exported fields.
+				} else if !sf.IsExported() {
+					// Ignore unexported non-embedded fields.
+					continue
+				}
+				tag := sf.Tag.Get("json")
+				if tag == "-" {
+					continue
+				}
+				name, opts := parseTag(tag)
+				if !isValidTag(name) {
+					name = ""
+				}
+				index := make([]int, len(f.index)+1)
+				copy(index, f.index)
+				index[len(f.index)] = i
+
+				ft := sf.Type
+				if ft.Name() == "" && ft.Kind() == reflect.Pointer {
+					// Follow pointer.
+					ft = ft.Elem()
+				}
+
+				// Only strings, floats, integers, and booleans can be quoted.
+				quoted := false
+				if opts.Contains("string") {
+					switch ft.Kind() {
+					case reflect.Bool,
+						reflect.Int, reflect.Int8, reflect.Int16, reflect.Int32, reflect.Int64,
+						reflect.Uint, reflect.Uint8, reflect.Uint16, reflect.Uint32, reflect.Uint64, reflect.Uintptr,
+						reflect.Float32, reflect.Float64,
+						reflect.String:
+						quoted = true
+					}
+				}
+
+				// Record found field and index sequence.
+				if name != "" || !sf.Anonymous || ft.Kind() != reflect.Struct {
+					tagged := name != ""
+					if name == "" {
+						name = sf.Name
+					}
+					field := StdField{
+						name:      name,
+						tag:       tagged,
+						index:     index,
+						typ:       ft,
+						omitEmpty: opts.Contains("omitempty"),
+						omitZero:  opts.Contains("omitzero"),
+						quoted:    quoted,
+					}
+					field.nameBytes = []byte(field.name)
+
+					// Build nameEscHTML and nameNonEsc ahead of time.
+					nameEscBuf = alg.HtmlEscape(nameEscBuf[:0], field.nameBytes)
+					field.nameEscHTML = `"` + string(nameEscBuf) + `":`
+					field.nameNonEsc = `"` + field.name + `":`
+
+					if field.omitZero {
+						t := sf.Type
+						// Provide a function that uses a type's IsZero method.
+						switch {
+						case t.Kind() == reflect.Interface && t.Implements(isZeroerType):
+							field.isZero = func(v reflect.Value) bool {
+								// Avoid panics calling IsZero on a nil interface or
+								// non-nil interface with nil pointer.
+								return v.IsNil() ||
+									(v.Elem().Kind() == reflect.Pointer && v.Elem().IsNil()) ||
+									v.Interface().(isZeroer).IsZero()
+							}
+						case t.Kind() == reflect.Pointer && t.Implements(isZeroerType):
+							field.isZero = func(v reflect.Value) bool {
+								// Avoid panics calling IsZero on nil pointer.
+								return v.IsNil() || v.Interface().(isZeroer).IsZero()
+							}
+						case t.Implements(isZeroerType):
+							field.isZero = func(v reflect.Value) bool {
+								return v.Interface().(isZeroer).IsZero()
+							}
+						case reflect.PointerTo(t).Implements(isZeroerType):
+							field.isZero = func(v reflect.Value) bool {
+								if !v.CanAddr() {
+									// Temporarily box v so we can take the address.
+									v2 := reflect.New(v.Type()).Elem()
+									v2.Set(v)
+									v = v2
+								}
+								return v.Addr().Interface().(isZeroer).IsZero()
+							}
+						}
+					}
+
+					fields = append(fields, field)
+					if count[f.typ] > 1 {
+						// If there were multiple instances, add a second,
+						// so that the annihilation code will see a duplicate.
+						// It only cares about the distinction between 1 and 2,
+						// so don't bother generating any more copies.
+						fields = append(fields, fields[len(fields)-1])
+					}
+					continue
+				}
+
+				// Record new anonymous struct to explore in next round.
+				nextCount[ft]++
+				if nextCount[ft] == 1 {
+					next = append(next, StdField{name: ft.Name(), index: index, typ: ft})
+				}
+			}
+		}
+	}
+
+	sort.Slice(fields, func(i, j int) bool {
+		a, b := fields[i], fields[j]
+		// sort field by name, breaking ties with depth, then
+		// breaking ties with "name came from json tag", then
+		// breaking ties with index sequence.
+		if c := strings.Compare(a.name, b.name); c != 0 {
+			return c < 0
+		}
+		if len(a.index) != len(b.index) {
+			return len(a.index) < len(b.index)
+		}
+		if a.tag != b.tag {
+			if a.tag {
+				return true
+			}
+			return false
+		}
+		return compare(a.index, b.index) < 0
+	})
+
+	// Delete all fields that are hidden by the Go rules for embedded fields,
+	// except that fields with JSON tags are promoted.
+
+	// The fields are sorted in primary order of name, secondary order
+	// of field index length. Loop over names; for each name, delete
+	// hidden fields by choosing the one dominant field that survives.
+	out := fields[:0]
+	for advance, i := 0, 0; i < len(fields); i += advance {
+		// One iteration per name.
+		// Find the sequence of fields with the name of this first field.
+		fi := fields[i]
+		name := fi.name
+		for advance = 1; i+advance < len(fields); advance++ {
+			fj := fields[i+advance]
+			if fj.name != name {
+				break
+			}
+		}
+		if advance == 1 { // Only one field with this name
+			out = append(out, fi)
+			continue
+		}
+		dominant, ok := dominantField(fields[i : i+advance])
+		if ok {
+			out = append(out, dominant)
+		}
+	}
+
+	fields = out
+	sort.Slice(fields, func(i, j int) bool {
+		a, b := fields[i], fields[j]
+		return compare(a.index, b.index) < 0
+	})
+
+	exactNameIndex := make(map[string]*StdField, len(fields))
+	foldedNameIndex := make(map[string]*StdField, len(fields))
+	for i, field := range fields {
+		exactNameIndex[field.name] = &fields[i]
+		// For historical reasons, first folded match takes precedence.
+		if _, ok := foldedNameIndex[string(foldName(field.nameBytes))]; !ok {
+			foldedNameIndex[string(foldName(field.nameBytes))] = &fields[i]
+		}
+	}
+	return StdStructFields{fields, exactNameIndex, foldedNameIndex}
+}
+
+func compare(s1, s2 []int) int {
+	for i, v1 := range s1 {
+		if i >= len(s2) {
+			return +1
+		}
+		v2 := s2[i]
+		if v1 != v2 {
+			return v1 - v2
+		}
+	}
+	if len(s1) < len(s2) {
+		return -1
+	}
+	return 0
+}
+
+type isZeroer interface {
+	IsZero() bool
+}
+
+var isZeroerType = reflect.TypeOf((*isZeroer)(nil)).Elem()
+
+// tagOptions is the string following a comma in a struct field's "json"
+// tag, or the empty string. It does not include the leading comma.
+type tagOptions string
+
+// parseTag splits a struct field's json tag into its name and
+// comma-separated options.
+func parseTag(tag string) (string, tagOptions) {
+	tag, opt, _ := strings.Cut(tag, ",")
+	return tag, tagOptions(opt)
+}
+
+// Contains reports whether a comma-separated list of options
+// contains a particular substr flag. substr must be surrounded by a
+// string boundary or commas.
+func (o tagOptions) Contains(optionName string) bool {
+	if len(o) == 0 {
+		return false
+	}
+	s := string(o)
+	for s != "" {
+		var name string
+		name, s, _ = strings.Cut(s, ",")
+		if name == optionName {
+			return true
+		}
+	}
+	return false
+}
+
+func isValidTag(s string) bool {
+	if s == "" {
+		return false
+	}
+	for _, c := range s {
+		switch {
+		case strings.ContainsRune("!#$%&()*+-./:;<=>?@[]^_{|}~ ", c):
+			// Backslash and quote chars are reserved, but
+			// otherwise any punctuation chars are allowed
+			// in a tag name.
+		case !unicode.IsLetter(c) && !unicode.IsDigit(c):
+			return false
+		}
+	}
+	return true
+}
+
+// dominantField looks through the fields, all of which are known to
+// have the same name, to find the single field that dominates the
+// others using Go's embedding rules, modified by the presence of
+// JSON tags. If there are multiple top-level fields, the boolean
+// will be false: This condition is an error in Go and we skip all
+// the fields.
+func dominantField(fields []StdField) (StdField, bool) {
+	// The fields are sorted in increasing index-length order, then by presence of tag.
+	// That means that the first field is the dominant one. We need only check
+	// for error cases: two fields at top level, either both tagged or neither tagged.
+	if len(fields) > 1 && len(fields[0].index) == len(fields[1].index) && fields[0].tag == fields[1].tag {
+		return StdField{}, false
+	}
+	return fields[0], true
+}
+
+
+// foldName returns a folded string such that foldName(x) == foldName(y)
+// is identical to bytes.EqualFold(x, y).
+func foldName(in []byte) []byte {
+	// This is inlinable to take advantage of "function outlining".
+	var arr [32]byte // large enough for most JSON names
+	return appendFoldedName(arr[:0], in)
+}
+
+func appendFoldedName(out, in []byte) []byte {
+	for i := 0; i < len(in); {
+		// Handle single-byte ASCII.
+		if c := in[i]; c < utf8.RuneSelf {
+			if 'a' <= c && c <= 'z' {
+				c -= 'a' - 'A'
+			}
+			out = append(out, c)
+			i++
+			continue
+		}
+		// Handle multi-byte Unicode.
+		r, n := utf8.DecodeRune(in[i:])
+		out = utf8.AppendRune(out, foldRune(r))
+		i += n
+	}
+	return out
+}
+
+// foldRune is returns the smallest rune for all runes in the same fold set.
+func foldRune(r rune) rune {
+	for {
+		r2 := unicode.SimpleFold(r)
+		if r2 <= r {
+			return r2
+		}
+		r = r2
+	}
+}